Protective coating



Nov. 1, 1938. Q R, PAYNE PROTECTIVE COATING Filed Sept. 20, 1937 Patented Nov. 1, 1938 UNITED STATES PATENT OFFICE PROTECTIVE COATING Clar on R. Payne, Allentown, Atlas Mineral Products Pa., assignor to The Company, Mertztown,

7 Claims.

This invention relates to improvements in protective coating, acid proof and water proof containers, walls and floors.

The invention has particular reference to the Walls and floors of tanks or vats for the pickling of steel and other metals and in the manufacture and handling of acids and other corrosive chemicals. The invention also has to do with the construction of acid proof floors, walls, drains, trenches and sewers.

An important object to be attained is the prduction of a seal for a chemically resistant structure permitting of differential expansion between the supporting body or structure for the protective sheathing. A further aim is to provide a coating of the character generally stated which allows for the differences in the coefiicient of expansion of the several materials which may be used in the construction of the body without disturbing the seal of the coating and which will insure at all times and under all normal conditions impervious and acid proof arrange ment.

A further object is to provide a protective coating and method for bodies of the character generally stated which. may be applied at a minimum expense and with a minimum of materials, which materials are of comparatively inexpensive construction, easily handled and yet which will insure at all times a proper protecttive coating for the body to which it is applied.

With these objects in view, together! with others which will appear as the description proceeds, the invention resides in the novel construction, combination. and arrangement hereinbefore fully described and claimed, reference being had to the attached drawing wherein:

Figure l is a perspective view of a conventional type of tank or vat wall and illustrating in. exaggerated form the several layers or courses of material employed in carrying forth the invention,

Figure 2 is a magnified cross section through a wall or floor constructed in accordance with the invention,

Figure 3 is a similar View showing a modification, and

Figure 4 is a sectional view showing how an expansion and contraction joint in the coating composition may be built in accordance with the invention.

Referring more particularly to Figures 1 and 2 of the drawing, 5 represents a wall or supporting structure of steel, wood, brick, concrete or other material, forming the main supporting structure for the tank or vat, or the floor as the case may be. The following description applies to a wall of a pickling tank or vat, but it will be understood that the same method described may equally as well be used in floor construction.

The inner surface of the supporting structure 5 has applied thereto an acid resisting substance 6 which should be plastic over a temperature range of from 0 F. to the maximum temperature to which it will be subjected in the struc- 1O ture, with a melting point in excess of the maximum of such temperature. It has been found that asphalt having the following characteristics is suitable for this layer:

Specific gravity at 60 F 1.008 Penetration at 77 F. 100/5 45 Melting point degrees Fahrenheit 210 This asphalt is melted and applied hot with a brush, mop or a squeegee, and usually several coats may be applied to build up a layer at least 4;" thick. Materials such as asbestos, silica, clay or slate may be added to the asphalt, if desired, providing the resulting mixture has the desired plasticity and melting point. Waxes, stearine, a pitch or other organic materials may be blended with the asphalt to obtain. desired properties. The asphalt or asphalt mixture may be dissolved in suitable solvents and applied cold instead of it being applied hot with a brush or mop.

When this acid resisting layer (5 has been applied, a body of acid proof cement l which may vary from A," to A, thick is applied over the said layer. This body 1 is strong, impervious and will not flow, sag or melt at the maximum temperature to which it will be subjected in use. This cement may contain a proper proportion of sulphur and a proper percentage of inert aggregate, while other plasticizing agents, minerals, fibers, etc. may be added with equal or better results. The composition of this cement may vary in accordance with the temperatures to which it will be subjected. This body or layer 1 must be inert to the chemicals used in the structure, and must be impervious to penetration by these chemicals. It must also have a high resistance to mechanical shock and must be of sufficient strength or rigidity to properly support the plastic layer 6. This cement is applied by melting and brushing on hot with a brush and several coats are applied in order that the proper thickness may be obtained. Some compositions, however, of this cement may be applied cold with a trowel.

The layer 8 is of plastic material and is an acid resisting substance similar the said layer varying in thickness from to The tile or brick lining for the tank is indicated at 9, if such lining is used, and the plastic layer 8 may be butted directly against the body or lining 9 if desired, or a cement l may be interposed between the tiling and the layer 8 if desired. The interposition of the layer It] assures the absence of voids between the layer 8 and the lining 9 for the collection and circulation of corrosive chemicals behind the said lining. The materials of which the layer It) is formed will vary with the temperature requirements of the wall or floor when in use.

The bodies or walls 9 may be of wood, brick, or other materials, and a priming coat of rubber base or asphalt base paint ll may be applied with a brush to the inner surface of the wall 5 prior to the application of the layer 6 to penetrate and close the pores of the structure and to insure proper adhesion between the body 5 and the layer 6. This coat is not absolutely essential and may be omitted.

In Figure 3 of the drawing there is illustrated a slight modification of the invention and wherein the improved protective coating is shown applied to a wooden, steel or concrete tank lined with lead. The outer wall is represented at 5 and the lead lining at I2, the protective coating layers being applied directly over the lead lining.

Figure 4 illustrates the manner in which expansion and contraction joints may be built in the composition of my invention to allow relative movement between the rigid cement body 1 and the plastic layers 6-8.

The use of the plastic layers above described allows diiierential movement between the outer supportingstructure 5 and the inner protective sheathing 9, while the impervious layer of acid proof cement sandwiched between the plastic layers prevents seepage of acid to the outer structure and also holds the plastic layers in place. In instances where the inner protective sheathing is of wood, it may be advantageous to omit the plastic layer next to the wooden sheathing and prevent a bond between such sheathing and the cement layer by applying a coating of clay to the back of the wooden sheathing in place of the layer 8. Such an arrangement would eliminate the possibility of the protective coating being exuded through shrinkage cracks in the Wood into the acid bath Within the container or vat.

The arrangement thus set forth in detail adeto the layer B,

- quately accomplishes the various objects set forth, and it will be understood that variations in the layer arrangement, and composition, may

layer of acid proof be resorted to without departing from the spirit of the invention as defined by the claims.

What I claim as new and useful is:

l. A chemically resistant structure including a rigid support, and, adhered thereto, a layer of acid resistant substance of plastic nature, a layer of acid proof cement, and a layer of acid resistant substance of plastic nature, in the order named, all of said layers being impervious to moisture.

2. A chemically resistant structure including a rigid support, and, adhered thereto, a layer of acid resistant mineral, a layer of acid proof cement, and a layer of acid resistant mineral, in the order named, all of said layers being impervious to moisture.

3. A chemically resistant structure including a rigid support and arranged therewith a pair of layers of acid resistant substances having a melting point in excess of the maximum temperature to which it will be subjected, one of said layers arranged and adhered upon each side of a layer of acid proof cement, all of said layers being impervious to moisture.

4. A chemically resistant structure including a rigid support, a pair of layers of acid resistant substance having a melting point in excess of the maximum temperature to which it will be subjected, a layer of acid proof cement interposed between and adhered to said pair of layers, and a coat of adhesive material securing a surface of one of said pairs of layers to said su port, said layers and coat being impervious to moisture.

5. A chemically resistant structure including a pair of rigid supports arranged in spaced parallel relation, a layer of acid resistant substance adhered to each of the adjacent faces of said supports, and an acid proof cement layer interposed between and adhered to the said layers.

6. A chemically resistant structure including a pair of rigid supports arranged in spaced parallel relation, a layer of acid resistant substance having a melting point in excess of the temperature to which it will be subjected adhered to each of the adjacent faces of said supports, and an acid proof cement layer interposed between and adhered to said layers.

7. A protective coating, comprising a pair of layers of acid and liquid resisting substance of substantial thickness, a rigid acid proof cement layer interposed between said layers, and the substance of said acid resisting material being plastic over a temperature range to the maximum temperature to which the coating will be subjected in use.

CLARON R. PAYNE. 

